Field of the Invention
Embodiments of the invention generally relate to an implantable device including an oxygen sensor, and a method of operating an implantable device that includes an oxygen sensor.
Description of the Related Art
Generally, oxygen sensors for implantation into the human or animal body are used for the measurement of the oxygen content in the blood, i.e. in cavities filled with blood, such as heart ventricles or blood vessels, and in the tissue with a blood supply. Typically, optical sensors may include three arrangements. In the case of the transmitted light method, generally, the blood or tissue is arranged between a source and a detector. In the case of the scattered light method, typically, the source radiates light into the tissue or blood, and the detector uses the reflected spectrum. In the case of the reflection method, generally, a mirror reflects the light emitted by the source onto the detector, and the blood or tissue to be examined is located in the two light paths—source/mirror and mirror/detector. For example, United States Patent Application Publication 20130289372 A1, entitled “Implantable Oximetric Measurement Apparatus and Method of Use”, to Imran, appears to disclose an apparatus, system, kit and method for in vivo measurement of blood oxygen saturation. In addition, for example, United States Patent Application Publication 20070239215 A1, entitled “Method and Apparatus for Using an Optical Hemodynamic Sensor to Identify an Unstable Arrhythmia”, to Bhunia et al., appears to disclose a medical device that identifies a hemodynamically instable arrhythmia based upon optical hemodynamic sensor signals. For example, Untied States Patent Application Publication 20070239052 A1, entitled “Method and Apparatus for Verifying a Determined Cardiac Event in a Medical Device Based on Detected Variation in Hemodynamic Status”, to Bhunia, appears to disclose detecting variations in hemodynamic status that includes a physiologic sensor sensing physiologic signals to generate a plurality of variation index samples corresponding to the sensed signals. In addition, for example, United States Patent Application Publication 20110190610 A1, entitled “Optical Sensor for Medical Device”, to Kuhn et al., appears to disclose a fixed lens spacing between emit and receive modules to achieve target sensor sensitivity, while varying other sensor parameters in order to increase signal amplitude without increasing power demand.
In view of the above, there is a need for a simple and reliable permanently implantable device, wherein oxygen content in the blood or tissue may be determined.
In addition, in view of the above, there is a need for a method and a device that determine the oxygen extraction rate of the heart, which allows for a quick-acting therapeutic measure.